CLEVELAND, Ohio -- If you want to see the underground bank vaults in the grand old Cleveland Trust building on Euclid Avenue and East Ninth Street, you'll need to score an invitation to a private event, or pay $10 to $20 to enter the opulently restored bar and lounge, The Vault at the 9, when it's open to the public Thursday, Friday and Saturday nights.

Or you can pick up the new mystery "The Dead Key" and "see" the vaults as they were decades ago, when the building was vacant, the bank long gone, and an abandoned vault held unclaimed safety deposit boxes still locked and filled with unknown treasures.

That's what Shaker Heights author D.M. Pulley discovered more than 10 years ago, when she worked as a civil engineer and was assigned to survey the adjacent Swetland building, at 1010 Euclid Ave.

The unopened boxes captured Pulley's imagination and led directly to "The Dead Key," which won the 2014 Amazon Breakthrough Novel Award and a $50,000 publishing contract from Amazon's Thomas and Mercer imprint. The book hit No. 1 on Amazon's Kindle best-seller list last week (it's now at No. 2) and comes out in paperback this week.

Pulley, who at 38 appears to take such unexpected glories in stride, received congratulations on those achievements with a smile, a slight blush and a modest understatement: "There's been a lot of change in my life lately," she said.

She had returned to the subterranean vaults for an interview on a recent weekday afternoon, when the place was empty except for staffers working to set up for a private party.

"You have to picture this without the fancy wallpaper and furniture," she said, gesturing toward the velvet-flocked wallpaper, leather couches and red-velvet drapes that give double meaning to the term "lush" for the city's latest hot cocktail lounge.

Pulley stood at the apex of the maze of secluded parlors and hideaway bars, trying to conjure the space as it was in 2001, when she and her boss wandered through the underground tunnels that connect the buildings.

"This was all dark and drippy and cold, with cobwebs hanging everywhere, like a dungeon," she said. One vault was lined floor to ceiling with safety deposit boxes, some of them with their doors hanging open. Keys lay scattered everywhere.

A security guard told them that many of the boxes were forgotten and abandoned when the bank closed in the mid-1990s.

"The records were lost of who owned them, and the double-key system was also lost," Pulley said. "The guard told me that survivors often don't know about the boxes, and if they do, they have to get permission to have them drilled open."

The beautiful bank building, one of the jewels of Cleveland architecture since it opened in 1908, intrigued Pulley. What was its story? Why was it vacant? Who left behind those mysterious unopened boxes, and why?

Five years ago, she decided to make the story up. She had quit her engineering job to stay home with her two young sons, who are now 8 and 5 years old. (She adopted the pen name D.M. Pulley to protect their privacy. "I know I'm a weirdo," she said. "But becoming a public figure wasn't part of my plan.")

"The stay-at-home mom thing didn't last too long before I got stir-crazy," she said.

She found that she had two hours every morning when her older son was in preschool and the baby napped. Determined not to waste those hours, she wrote the book that had been on her mind for all those years.

Within eight months of writing every day but weekends, she had a manuscript of 180,000 words -- twice the length of the average mystery.

Her husband, Irv, read every word, making suggestions along the way and filling the roles of cheerleader and supporter.

"Then we had the work of editing and figuring out what was there," she said.

When she realized she needed some guidance, Pulley sent drafts out to friends and family for feedback and hired a freelance editor out of New York. After all the revisions, in the summer of 2012, she queried five literary agents.

She got five rejections. Discouraged, she put the manuscript away for a while.

"Then when this contest popped up, I thought, 'What the hell, I'll just see what happens.' "

And so she entered the 2014 Amazon Breakthrough Novel Award -- along with 10,000 other unpublished writers. She cut 30,000 words to fit the contest rules, and sent it in on Feb. 15, just making the deadline.

"It was a Hail Mary shot," she said. "I was just hoping for a Publishers Weekly review that I could use to try to sell the book."

Publishers Weekly, one of the partners in the contest, reviewed the entries, which were judged in four elimination rounds by the magazine's staff and other publishing professionals. The public, a la "American Idol", decided the final round.

Pulley learned she had made it to the last round of five finalists in early July. Two weeks later, she won the grand prize.

"It's been a surreal year," she said. "The whole thing is so lucky and has so many lucky coincidences. You couldn't write it this well."

Chief among the well-timed coincidences is the restoration of the buildings by the Geis Cos., who bought the complex of bank buildings in 2013 for $27 million, and spent a reported $170 million turning them into venue that includes a luxury hotel, high-end apartments, offices, dining and entertainment spots, and, capping it all off, a Heinen's Fine Foods grocery story occupying the exquisite, stained-glass-topped Cleveland Trust Rotunda.

"After all the scandals and false starts [at renovating the complex], the fact that it was finished just before my book was published is amazing," she said.

Just as civic leaders and critics praise the Geis restoration, book reviewers have praised Pulley's use of the bank complex as her setting for the two plot threads, which take place in 1978 and 1998.

"The author imbues the bank with great physical presence, its architecture, floor plans and structure all meticulously described, creating a setting that feels alive and haunted," noted the review in the industry magazine Kirkus.

And in The Plain Dealer and on cleveland.com, reviewer Laura DeMarco wrote: "...for Clevelanders, it will certainly be Pulley's evocation of Cleveland's past that is the book's key appeal. ... (f)rom the bank's gilded vault and swanky offices to gritty Euclid Avenue, the raucous Theatrical Grill, elegant Stouffer's Inn and the dodgy Lancer Motel."

Still, Pulley emphasized that her story, while set in familiar locations and touching on Cleveland history, is fiction. "It's not intended to be a scholarly work," she said. "It was just inspired by some of the events in the city's history."

The book was also inspired by those wonderful old Cleveland buildings, by their history and construction. Not surprisingly, Pulley has done a lot of work in historic preservation of buildings through the engineering company she owns and runs.

"I'm passionate about it," she said.

Now her passion has shifted from engineering to writing. She put her company on hold to write her second novel, another mystery set in the past -- this time, the 1950s, in rural Michigan.

She just finished the first draft and is eager to start on the revisions, but concedes that she might not get to it right away. She has a novel to promote, interviews scheduled and a book launch party planned for Saturday, Feb. 28 at -- where else? -- The Vault at the 9.

The public is invited to the party and book signing, which takes place from 9 to 11 p.m. at the Metropolitan Hotel, 2017 East Ninth St. And though you will still have to pay the admission -- $20 for men, $10 for women -- you will get half off if you purchase the book.